Loading mechanism for a shaker hearth heat-treating furnace

ABSTRACT

A heat-treating furnace of the type having a hearth that is agitated endwise back and forth to advance workpieces through the heating chamber. The workpieces are delivered to one end of the hearth through an opening in the furnace above the hearth and the opening is controlled by a sliding door. Adjacent the opening is a hopper which collects workpieces and which includes a chute that may be moved to an operative position in which the workpieces in the hopper slide down the chute, through the opening and onto the hearth. A power actuator is connected to both the door and the chute and simultaneously opens the door and moves the chute to its operative position.

Burmeister et a].

[ Feb. 15, 1972 LOADING MECHANISM FOR A SHAKER "EARTH HEAT-TREATING FURNACE Inventors: Karl-Heinz Burmeister, Kleve; Wilhelm Hoenselaer, Kleve-Materborn; Lothar Moes, Goch, all of Germany Assignee: Aleo Standard Corporation, Valley Forge, Pa. by said Karl Heinz Burmeister and Wilhelm Hoenselaer Filed: Apr. 15, 1970 Appl. No.: 28,653

Foreign Application Priority Data Apr. 26, 1969 Germany ..P 19 21 407.4

US. Cl. ..263/2l C, 214/35 R Int. Cl ..F27b 3/06 Field of Search ..263/2l C; 214/35 R, 303;

[56 References Cited UNITED STATES PATENTS 3,365,182 l/l968 lpsen ..263/2l C Primary Examiner-John J. Camby Altomey-Wolfe, Hubbard, Leydig, Voit & Osann [57] ABSTRACT A heat-treating furnace of the type having a hearth that is agitated endwise back and forth to advance workpieces through the heating chamber. The workpieces are delivered to one end of the hearth through an opening in the furnace above the hearth and the opening is controlled by a sliding door. Adjacent the opening is a hopper which collects workpieces and which includes a chute that may be moved to an operative position in which the workpieces in the hopper slide down the chute, through the opening and onto the hearth. A power actuator is connected to both the door and the chute and simultaneously opens the door and moves the chute to its operative position.

7 Claims, 6 Drawing Figures LOADING MECHANISM FOR A SHAKER IIEARTII HEAT-TREATING FURNACE BACKGROUND OF THE INVENTION This invention relates to a furnace for heat-treating metal workpieces fed through a heating chamber on a shaker hearth which is agitated endwise back and forth to advance the workpieces through the chamber. Usually, the latter is filled with an inert gas to prevent oxidation of the workpieces. More particularly, the invention relates to a furnace in which the workpieces are collected outside the furnace in a hopper and are deposited in batches on one end of the hearth through an opening in the furnace above the hearth, the opening being controlled by a door.

SUMMARY OF THE INVENTION The general object of the invention is to provide a shaker hearth furnace with a new and improved loading mechanism which assures that the hopper is completely emptied each time it delivers workpieces to the hearth, thereby giving better control over the amount of workpieces delivered to the hearth, and which also minimizes the possibility of workpieces preventing the door from closing completely, thereby eliminating excessive losses of the inert gas from the furnace chamber.

A more detailed object is to achieve the foregoing by providing the hopper with a chute which is movable to an emptying position in which it extends to the opening to insure that workpieces are not caught or clogged in the hopper.

Another object is to arrange the door so that it is separate from the hopper thereby reducing the possibility of workpieces in the hopper interfering with the proper operation of the door.

A further object is to operate both the door and the chute from a common power source to insure that the chute no longer is transferring workpieces to the hearth when the door is closed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary longitudinal sectional view of a furnace utilizing one form of the novel loading mechanism of the present mventron.

FIG. 2 is a view similar to FIG. 1 but shows the parts in a moved position.

FIG. 3 is a fragmentary perspective view of the loading mechanism.

FIG. 4 is a fragmentary longitudinal sectional view of a furnace utilizing a modified form of the loading mechanism.

FIG. 5 is a view similar to FIG. 4 but shows the parts in a moved position.

FIG. 6 is a fragmentary perspective view of the modified loading mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes of illustration, the invention is embodied in a furnace of the shaker-hearth-type for the pieces heat-treating metal workpieces 10. The furnace is formed by a walled enclosure 11 lined with suitable insulating material 12 such as fire brick to define a heating chamber 13. The latter is heated by any conventional means (not shown) to raise the temperature and thus treat the workpieces passed through the chamber. Usually, the atmosphere within the chamber is controlled such as by flowing an inert gas into the chamber to prevent oxidation of the pieces as they are treated.

In a furnace of this type, a hearth 14 holds the workpieces on a generally horizontal surface and the hearth is agitated back and forth to advance the workpieces through the chamber 13, the hearth moving first relatively slowly in the forward direction to advance the workpieces and then retracted rapidly so the inertia of workpieces slides them step by step along the hearth surface and through the chamber.

Such agitation, or reciprocating movement, of the hearth 14 is produced by a shaker mechanism 15 mounted on a support 16 which is secured to the enclosure 11 and which constitutes a vestibule of the enclosure. In this instance, the mechanism includes a pneumatic motor 17 of the pistonand cylinder-type with the rod 18 of the piston moving back and forth along a path parallel to the path of the work through the chamber 13. The rod is fastened to a bracket 19 on the underside of the hearth which is supported by rollers 20 so that the motor moves the hearth back and forth between the solid and broken lines shown in FIG. 1.

The workpieces 10 are delivered to one end of the hearth 14 in batches through an opening 21 in a wall 22 of the enclosure 11 above this end of the hearth. For this purpose, a hopper 23 is mounted on the enclosure 11 and receives and collects workpieces which, herein, are delivered to the hopper by an endless belt conveyor 24. Periodically, the hopper is emptied and its contents delivered to the hearth 14 through the opening 21. The latter is controlled by a door 25 which normally closes the opening but moves to an open position (see FIG. 2) when the workpieces are being delivered from the hopper to the hearth. A nozzle 26 producing a pilot flame 27 is disposed adjacent the opening 21 to burn escaping atmosphere, especially when the door 25 is open.

In accordance with the present invention, the hopper 23 and the door 25 are constructed and correlated in anovel manner to produce more accurately controlled delivery of the workpieces 10 to the hearth 14 and to minimize the possibility of incomplete closing of the door. For these purposes, the hopper 23 is formed with a chute 28 which is movable to an emptying position in which it extends over the opening 21 to insure that workpieces are not caught or clogged in the hopper and the door 25 is made as an element separate from the hopper to reduce the possibility of workpieces interferring with the proper operation of the door. Preferably, both the chute 28 and the door 25 are operated from a common power source 29 to insure that the chute has completed its function of transferring workpieces to the hearth 14 before the door is closed. Moreover, the door is behind the chute when the hopper is being emptied to further insure that workpieces do not interfere with the closing of the door.

In the form of the invention illustrated in FIGS. 1 through 3, the opening 21 is in the top wall 22 of the vestibule portion 16 of the enclosure 11 and the door 25 slides back and forth on this wall between a closed position over the opening (FIG. 1) and an open position (FIG. 2) alongside the outer edge 30 of the opening. The door is guided by angles 31 welded to the wall 22. The hopper 23, which is generally V-shape in transverse cross section, is supported on the top of the vestibule 16 by a frame 32 which is bolted to the top wall 22. The wall 33 (FIG. 3) of the hopper adjacent the opening 21 stops short of the hopper bottom to leave an opening 34 through which the workpieces may flow out of the hopper by gravity.

Herein, the chute 28 is a separate and the only movable part of the hopper 23 and comprises a rectangular plate 35 pivotally mounted by a pin 36 to swing about a horizontal axis extending along the bottom of the hopper. The plate is on the same side of the hopper as the hopper wall 33 so that, when the plate is swung up to the position shown in FIG. 1, it prevents the workpieces from flowing out of the hopper through the opening 34. The plate 35 may be lowered to the position illustrated in FIGS. 2 and 3 in which it overhangs the adjacent edge 30 of the opening. In this position of the plate, the workpieces in the hopper flow through the opening 34, down the plate, through the opening 21 and onto the hearth 14. A lip 37 on the free edge of the plate projects into the opening 21 to insure that all the workpieces enter the furnace and flanges 38, which are formed on the side edges of the plate and slide along the sidewalls 39 of the hopper, keep the workpieces on the plate as they flow to the furnace.

The actuator 29 may be a pneumatic cylinder mounted horizontally on the end of the vestibule 16 by means of a bracket 40 and the rod 41 of the piston (not shown) projects over the top wall 22 of the vestibule 16. The outer end of the rod 41 is connected to a bracket 42 secured to the top of the door 25 so that the rod slides the door back and forth between the open and closed positions under the control of the cylinder 29. An adjustable link 43 is pivotally connected at one end to the bracket 42 and at the other end to a bracket 44 on the outer side of the plate 35 so that the chute 28 swings from its upper position to its emptying position and back as an incident to the sliding of the door 25 from its closed position to the open position and back. This simultaneous operation of the door and the chutes insures that the door is open when the hopper 23 is emptied and, thus, that workpieces do not interfere with the full closing of the door. Contributing to this result is the arrangement by which the door, when opened, is positioned under the hopper and the chute.

FIGS. 4 through 6 illustrate a modified form of the invention and corresponding parts are identified by the same but primed reference characters. In this instance, the hopper 23 and the door 25, when in its open position, are between the opening 21 and the furnace l1 and, to accommodate this, the vestibule 16' is somewhat longer than in the first embodiment, With the longer vestibule, the'cylinder 17' is placed inside but the piston rod 18 still is connected to the hearth 14 through a bracket 19' to vibrate the hearth. The cylinder 29' is mounted, by means ofa bracket 40', on the top wall 22' of the vestibule between the opening 21 and the furnace 11 and its rod 41 pulls the door 25', which slides in angles 31', from the closed position (FIG. 4) to the open position (FIG.

In this form of the invention, the chute 28' is a rigid part of the hopper 23' and constitutes an inclined wall thereof. Laterally spaced posts 32 fixed to the wall 22' pivotally support the hopper 23' by means of trunnions 45 so that the hopper may turn back and forth between the collecting position shown in FIG. 4 and the emptying position illustrated in H08. 5 and 6. To turn the hopper back and forth between these positions as an incident to opening and closing of the door 25, adjustable links 43 are pivotally connected at one of their ends to brackets 42 on the door 25' and at the other of their ends to the sides of the hopper along an axis spaced from the axis of the trunnions 45. Thus, when the door is in the closed position, the links support the hopper in the upright or collecting position and, when the door slides to the open position, the link turns the hopper to the emptying position with the end of the chute portion 28' of the hopper adjacent the edge 30 of the opening 21'. A lip 37' formed on this end of the chute overhangs the edge 30' to help guide the workpieces through the opening 21'.

When the door is open and the hopper 23 and chute 28' are in the emptying position, the conveyor 24' continues to deliver workpieces and, in this embodiment, it delivers the workpieces directly to the hearth 14' through the opening 21. Thus, the delivery end of the conveyor is directly above the opening and a collar 46 insures that these workpieces as well as those being emptied from the hopper enter the opening 21'. Herein, the collar is generally U-shaped with the walls 47 flaring outwardly and the collar is rigid with the door 25 to slide back and forth with the latter on the top wall 22'. When the door is open, the opening 21 is surrounded by the three walls 47 of the collar and the chute portion 28 of the hopper.

The collar 46 may conveniently be used to provide the pilot flames 27. For this purpose, the upper edge portions 48 of the walls 47 are formed as a tubular conduit and a combustible gas is introduced into the latter through a flexible conduit 49 (FIG. 6). The gas flows out of the conduit 49 through orifices 50 to support the pilot flames.

It will be observed that, with the present invention as described above, the door 25 is separate from the hopper 23 and the chute 28 and does not interfere with the complete emptying of the hopper. Also, with this arrangement, there is little likelihood of workpieces interfering with the full closing of the door. By using a common actuator 29 to operate both the door and the chute, the proper sequence of operation of these two parts is assured.

We claim as out invention: 1. In a heat-treating furnace, the combination of, a walled enclosure defining a treating chamber, an elongated generally horizontal hearth disposed in said chamber and adapted to receive workpieces to be treated, means for shaking said hearth to advance the workpieces through said chamber, a wall of said enclosure having an opening disposed above one end of said hearth, a door mounted on said enclosure and movable between open and closed positions relative to said opening, a hopper supported on said enclosure exteriorly thereof and adjacent said opening and adapted to store workpieces, said hopper including a chute movable up and down between a first position in which it holds the workpieces in the hopper and a second position in which it permits workpieces to fall from the hopper and directs the workpieces through said opening and onto said hearth, a reversible power actuator, and mechanism connecting said actuator to said door and said chute and operable when the actuator is moved in one direction simultaneously to open said door and to move said chute down to said second position, said mechanism being operable when said actuator is moved in the opposite direction to move said chute up to said first position and move said door to said closed position.

2. Apparatus as defined in claim 1 in which said door when in said open position is behind said chute when the latter is in said second position.

3. Apparatus as defined in claim 1 in which said door slides on said wall between said open and closed positions.

4. Apparatus as defined in claim 3 in which said mechanism includes a first connection between said actuatorand said door and a second connection between said door and said chute.

5. Apparatus as defined in claim 1 in which said chute is formed with a lip across the outer end of the chute, said lip projecting into said opening and said door being behind said lip when said chute is in said second position.

6. Apparatus as defined in claim 4 in which said door slides between said open and closed positions and said chute is mounted to swing between said first and second positions.

7. Apparatus as defined in claim 1 in which said chute is mounted to swing between said first and second positions. 

1. In a heat-treating furnace, the combination of, a walled enclosure defining a treating chamber, an elongated generally horizontal hearth disposed in said chamber and adapted to receive workpieces to be treated, means for shaking said hearth to advance the workpieces through said chamber, a wall of said enclosure having an opening disposed above one end of said hearth, a door mounted on said enclosure and movable between open and closed positions relative to said opening, a hopper supported on said enclosure exteriorly thereof and adjacent said opening and adapted to store workpieces, said hopper including a chute movable up and down between a first position in which it holds the workpieces in the hopper and a second position in which it permits workpieces to fall from the hopper and directs the workpieces through said opening and onto said hearth, a reversible power actuator, and mechanism connecting said actuator to said door and said chute and operable when the actuator is moved in one direction simultaneously to open said door and to move said chute down to said second position, said mechanism being operable when said actuator is moved in the opposite direction to move said chute up to said first position and move said door to said closed position.
 2. Apparatus as defined in claim 1 in which said door when in said open position is behind said chute when the latter is in said second position.
 3. Apparatus as defined in claim 1 in which said door slides on said wall between said open and closed positions.
 4. Apparatus as defined in claim 3 in which said mechanism includes a first connection between said actuator and said door and a second connection between said door and said chute.
 5. Apparatus as defined in claim 1 in which said chute is formed with a lip across the outer end of the chute, said lip projecting into said opening and said door being behind said lip when said chute is in said second position.
 6. Apparatus as defined in claim 4 in which said door slides between said open and closed positions and said chute is mounted to swing between said first and second positions.
 7. Apparatus as defined in claim 1 in which said chute is mounted to swing between said first and second positions. 